From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 33E0FC433E6 for ; Thu, 11 Mar 2021 14:04:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DE2F464FAD for ; Thu, 11 Mar 2021 14:04:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233729AbhCKODi (ORCPT ); Thu, 11 Mar 2021 09:03:38 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:59134 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232949AbhCKODc (ORCPT ); Thu, 11 Mar 2021 09:03:32 -0500 Received: from 1.general.cking.uk.vpn ([10.172.193.212]) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1lKLuU-0005MP-RV; Thu, 11 Mar 2021 14:03:30 +0000 Subject: Re: pinctrl: core: Handling pinmux and pinconf separately To: Michal Simek Cc: Linus Walleij , "linux-gpio@vger.kernel.org" , "linux-kernel@vger.kernel.org" References: <5c08bd61-688f-e95b-5fa3-584f190ed4bf@xilinx.com> From: Colin Ian King Message-ID: <34c61597-a90b-5d90-f9fb-4ede3ece3b4c@canonical.com> Date: Thu, 11 Mar 2021 14:03:30 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/03/2021 11:28, Michal Simek wrote: > > > On 3/11/21 12:24 PM, Colin Ian King wrote: >> On 11/03/2021 11:16, Michal Simek wrote: >>> >>> >>> On 3/11/21 11:57 AM, Colin Ian King wrote: >>>> Hi, >>>> >>>> Static analysis on linux-next with Coverity has found a potential issue >>>> in drivers/pinctrl/core.c with the following commit: >>>> >>>> commit 0952b7ec1614abf232e921aac0cc2bca8e60e162 >>>> Author: Michal Simek >>>> Date: Wed Mar 10 09:16:54 2021 +0100 >>>> >>>> pinctrl: core: Handling pinmux and pinconf separately >>>> >>>> The analysis is as follows: >>>> >>>> 1234 /** >>>> 1235 * pinctrl_commit_state() - select/activate/program a pinctrl state >>>> to HW >>>> 1236 * @p: the pinctrl handle for the device that requests configuration >>>> 1237 * @state: the state handle to select/activate/program >>>> 1238 */ >>>> 1239 static int pinctrl_commit_state(struct pinctrl *p, struct >>>> pinctrl_state *state) >>>> 1240 { >>>> 1241 struct pinctrl_setting *setting, *setting2; >>>> 1242 struct pinctrl_state *old_state = p->state; >>>> >>>> 1. var_decl: Declaring variable ret without initializer. >>>> >>>> 1243 int ret; >>>> 1244 >>>> >>>> 2. Condition p->state, taking true branch. >>>> >>>> 1245 if (p->state) { >>>> 1246 /* >>>> 1247 * For each pinmux setting in the old state, forget >>>> SW's record >>>> 1248 * of mux owner for that pingroup. Any pingroups >>>> which are >>>> 1249 * still owned by the new state will be re-acquired >>>> by the call >>>> 1250 * to pinmux_enable_setting() in the loop below. >>>> 1251 */ >>>> >>>> 3. Condition 0 /* !!(!__builtin_types_compatible_p() && >>>> !__builtin_types_compatible_p()) */, taking false branch. >>>> 4. Condition !(&setting->node == &p->state->settings), taking true >>>> branch. >>>> 7. Condition 0 /* !!(!__builtin_types_compatible_p() && >>>> !__builtin_types_compatible_p()) */, taking false branch. >>>> 8. Condition !(&setting->node == &p->state->settings), taking true >>>> branch. >>>> 11. Condition 0 /* !!(!__builtin_types_compatible_p() && >>>> !__builtin_types_compatible_p()) */, taking false branch. >>>> 12. Condition !(&setting->node == &p->state->settings), taking false >>>> branch. >>>> >>>> 1252 list_for_each_entry(setting, &p->state->settings, >>>> node) { >>>> >>>> 5. Condition setting->type != PIN_MAP_TYPE_MUX_GROUP, taking true >>>> branch. >>>> 9. Condition setting->type != PIN_MAP_TYPE_MUX_GROUP, taking true >>>> branch. >>>> 1253 if (setting->type != PIN_MAP_TYPE_MUX_GROUP) >>>> 6. Continuing loop. >>>> 10. Continuing loop. >>>> >>>> 1254 continue; >>>> 1255 pinmux_disable_setting(setting); >>>> 1256 } >>>> 1257 } >>>> 1258 >>>> 1259 p->state = NULL; >>>> 1260 >>>> 1261 /* Apply all the settings for the new state - pinmux first */ >>>> >>>> 13. Condition 0 /* !!(!__builtin_types_compatible_p() && >>>> !__builtin_types_compatible_p()) */, taking false branch. >>>> 14. Condition !(&setting->node == &state->settings), taking true branch. >>>> 1262 list_for_each_entry(setting, &state->settings, node) { >>>> 15. Switch case value PIN_MAP_TYPE_CONFIGS_PIN. >>>> >>>> 1263 switch (setting->type) { >>>> 1264 case PIN_MAP_TYPE_MUX_GROUP: >>>> 1265 ret = pinmux_enable_setting(setting); >>>> 1266 break; >>>> 1267 case PIN_MAP_TYPE_CONFIGS_PIN: >>>> 1268 case PIN_MAP_TYPE_CONFIGS_GROUP: >>>> >>>> 16. Breaking from switch. >>>> >>>> 1269 break; >>>> 1270 default: >>>> 1271 ret = -EINVAL; >>>> 1272 break; >>>> 1273 } >>>> 1274 >>>> >>>> Uninitialized scalar variable (UNINIT) >>>> 17. uninit_use: Using uninitialized value ret. >>>> >>>> 1275 if (ret < 0) >>>> 1276 goto unapply_new_state; >>>> >>>> For the PIN_MAP_TYPE_CONFIGS_PIN and PIN_MAP_TYPE_CONFIGS_GROUP >>>> setting->type cases the loop can break out with ret not being set. Since >>>> ret has not been initialized it the ret < 0 check is checking against an >>>> uninitialized value. >>>> >>>> I was not sure if the PIN_MAP_TYPE_CONFIGS_PIN and >>>> PIN_MAP_TYPE_CONFIGS_GROUP cases should be setting ret and if so, what >>>> the value of ret should be set to (is it an error condition or not?). Or >>>> should ret be initialized to 0 or a default error value at the start of >>>> the function. >>>> >>>> Hence I'm reporting this issue. >>> >>> What about this? Is this passing static analysis? >> >> It will take me 2 hours to re-run the analysis, but from eyeballing the >> code I think the assignments will fix this. > > would be good if you can rerun it and get back to us on this. > I will wait if something else will pop up and then will send v2 with > this that Linus can apply this one instead. Yep, passed, fixes the issue found by Coverity. > > Thanks, > Michal > > >